High dielectric constant materials with high bulk resistivity are needed to reduce the size of capacitors in analog CMOS devices, to reduce the size of the high voltage capacitors in charge pumps of high voltage CMOS devices and to reduce the size of capacitors of intelligent MEMS devices.
Many materials have been investigated to produce these materials, including barium strontium titanate (BST), lead zirconate titanate (PbZrO3-PbTiO3, PZT) and other such high dielectric constant materials.
Unfortunately, even if these materials can achieve high dielectric constants, they generally have a leakage current higher then about 1 μA/cm2 when exposed to an electrical field higher than about 0.1 MV/cm.
Various titanium silicate thin films have been deposited using pulsed laser deposition (PLD): D. K. Sarkar, E. Desbiens, and M. A. El Khakani, Appl. Phys. Lett. 80, 294 (2002).
More recently, the deposition technique migrated to radio-frequency magnetron sputtering of a TiO2/SiO2 composite target in a reactive O2/Ar gas atmosphere. This technique allowed the deposition of titanium silicate thin films with a dielectric constant as high as 20 and a low leakage current density of about 1 mA/cm2 at 0.1 MV/cm: D. Brassard, D. K. Sarkar, M. A. El Khakani, and L. Ouellet, (JUST submitted).
Other researchers have also published on the deposition of titanium silicates using the radio-frequency sputtering:                Nishiyama, A. Kaneko, M. Koyama, Y. Kamata, I. Fujiwara, M. Koike, M. Yoshiki and M. Koike, Mat. Res. Soc. Symp. Proc. 670, K4.8.1 (2001)        M. Koyama, A. Kaneko, M. Koike, I. Fujiwara, M. Yabuki, M. Yoshiki, M. Koike, and A. Nishiyama, Mat. Res. Soc. Symp. Proc. 670, K4.7.1 (2001)        X. Wang, H. Masumoto, and Y. Someno, T. Hirai, Thin Solid Films 338, 105 (1999)        M. F. Ouellette, R. V. Lang, K. L. Yan, R. W. Bertram, and R. S. Owles, J. Vac. Sci. Technol. A9, 1188 (1991)        R. P. Netterfield, P. J. Martin, C. G. Pacey, and W. G. Sainty, J. Appl. Phys. 66, 1805 (1989)        
Spin-on technologies have been patented by DALSA Semiconductor to deposit high quality dielectrics as described in the following patents: Luc Ouellet, U.S. Pat. No. 5,470,798 Moisture-free SOG process; Luc Ouellet, U.S. Pat. No. 5,457,073 Multi-level interconnection CMOS devices with SOG; Luc Ouellet, U.S. Pat. No. 5,447,613 Preventing of via poisoning by glow discharge induced desorption; Luc Ouellet, U.S. Pat. No. 5,364,818 SOG with moisture resistant protective capping layer; Luc Ouellet, U.S. Pat. No. 5,320,983 Spin-on glass processing technique for the fabrication of semiconductor devices; and Luc Ouellet, U.S. Pat. No. 5,270,267 Curing and passivation of spin on glasses by a plasma process wherein an external polarization field is applied to the substrate.
DALSA Semiconductor has described techniques to achieve high value capacitors in semiconductor devices (indicating the need to go toward TiO2-like materials in combination with SiO2): U.S. Pat. No. 6,268,620, Method of forming capacitors on integrated circuit; and U.S. Pat. No. 6,083,805, Method of forming capacitors in a semiconductor device
The spin-on sol-gel technique of deposition of titanium silicates has been reported by various investigators:                Y. Sorek, R. Reisfeld, I. Finkelstein, and S. Ruschin, Appl. Phys. Lett. 63, 3256 (1993)        X. Orignac, D. Barbier, X. M. Du, and R. M. Almeida, Appl. Phys. Lett. 69, 895 (1996)        A. M. Seco, M. C. Gongalves, and R. M. Almeida, Mater. Sci. Eng., B76, 193 (2000)        
However, these studies merely investigate the structural and optical properties of titanium silicate films.